Filakd



W. B. MAHQUARD.

COKNG PROCESS.

APPLICAT'ON FILED JAILZ, l9l9.

Patented Dec. 2, 1919.

2 SHEETS-SHEET NVENTOR.

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IYe/a hue A TTORNEYS.

WILLIAM B. MARQUARID, OF EASTON, PENNSYLVANIA.

- 001mm rnocnss.

Specification of Letters Patent.

Patented Dec. 2, 1919.

Application filed January 2, 1919. Serial No. 269,324.

To all whom it may concern:

Be it known that I, WiLLlAM 15. MAR- omno, o citizen of the UnitedStates, residing in the city of Euston, county of Northampton, and Stateof Pennsylvania, have invented certain new and useful Improvements inCoking Processes, of which the following is a specification.

The retort by-product oven used most extensively in this country is along narrow chamber, from 30 to $0 feet in length, about 7 feet high.:Jl'fil from 15 to 20 inches wide. The ovens are built in lllOClii') orbatteries, having from 20 to ill) ovens in ouch buttery; adjoining;-ovens are separated by a line in 'r-shich the heating gas is burned tocolic lhe coal with which the ovens are charged. The charge of coal isintroduced into the ovens througl'i openings in the top, after which theopenings are sealed and thegas and other distillation products are ledaway through on opening to the collecting main. W hen the charge of coalis coked, which occurs in from 16 to 24 hours, the doors at the ends ofthe oven are removed and the (OlCC is pushed out by means of nuns orpushers; the oven doors are then immediately closed and sealed, and theoven is then ready for a fresh charge of coal. The liberated gases anddistillation products pass from the collecting main and are exhaustedinto the condensing house Where the gases are cooled and the by-productsere removed. About one half of the as is returned to the ovens to beburned in t he fines, and the remainder is otherwise utilized as anadditional by,- product, My improvements are specifically applicable tothe coking process us time generally described. l

The successful operation of-a byroduct coking plant depends mainly upont e uniformity of the hentingof the ovens. Endless trouble results fromirregular or nonuniform hcnting. One of the main considerations insecuring uniform hosting: is the proper order of rotation in dischargingthe ovens, If there is a. predetermined order of. discharging the ovens.such order is culled the pushing series. My improvcn'ients rclate to theselection of the best order of discharging the'ovens, or in other Words,the selection of the best pushing" series to secure the greatest economyend-efficiency in a coking plant.

Pushing series may be generally classified as uniform and non-uniform orirregular. If there is e constant (lifi'erenoe in the ages of every twoadjacent ovens, the pushing series is culled uniform; and if thatdifference is not constant, then the pushing series is callednon-uniform or irregular. A uniform pushing series may also be definedas one in which the first oven at the right of any oven at the time ofits dis charge is always of the same age; likewise the age of the firstoven on the left is :1]- wuys the same.

\Vhen a uniform pushing series is used, if the heating gas is burneduniformly in all of the lines, all of the ovens Will receive identicallythe some heat trei-ttment. With a. non-uniform or irregular pushingseries, the heating conditions may difi'er widely and some ovens mayreceive much more heat than others, notwithstanding the burners in thevarious flues are regulated to liberate a uniform amount of heel: andthe coking time is the same for all of the ovens. It must notbe'inferr'ed that all uniform series are more efficient than some of thenon-uniform series; the exact reverse is true in many cases. The ovensmay be uniformly poorly heated.

The ideal condition for the greatest .efliciency is such that thepushing series should be uniform, and such as to maintain a more clearlyconstant flue temperature. The temperature of the flue is dependent uponthe difference in the ages of the adjoining charges of coal, providedthe amount of h at liberated in the fines is constant. If the differencein the ages of the charges of two adjacent ovens is small, the fluebetween them is cooled down in the early part of the coking time. andconsequently a lesser amount of heat can pass through the flue wallsthan could pass if the flue temperature remained constant or nearly so;While in the latter part of the coking time. when both ovens have a hightemperature, the rate of flow of heat from the fine to the ovens is muchreduced and consequently the heat in the flues must either he carriedout with the produ .ts of combustion or the ten'iperutures of t e fluesbecomes verv hie-h. Prue tically. the flue temg'ierature increases andas a result more heat is carried out of the tines hy the products o'lcombustion. Beering in mind that the rate of [low of heat variesdirectly as the ditfcrenee in the to wraturcs of the flue and the ovenwalls, it u ill be seen that the ideal difference in the ages ofadjacent ovens is eiizt'bt'ly one half the coking; time, l'iecause whenthe difference in ages is one half the coking time lhore is a moreconstant total flow of heat from the fine to the two adjacent ovens.Thus it the oven to the left of a flue is newly charged and receivesmuch heat, the oven to the right is half coked and receives considerablyless heat; and hence, when the oven to the right is recharged andreceives much heat, the oven to the left is half colved and receives asmaller amount of heat. Therefore, the H no tmnperatu re will be more.uniform when the difference in the ages of adjacent ovens is one half ofthe coking time than it is when the ditfercnce in the ages of :uljaceutovens is greater or less than one half the coking time.

.\l v innmovements, therefore. aim to meet the ideal condition as nearlyas practicable. be having:

I lst. Uniform heat treatment of all oven by establishing 2 uniformpushing series. End. The difference in the ages of adjacent ovens asnearly as practicable one half of the coking time in order to maintainmore uniform temperature of the fines.

A uniform and ideal pushing series can also be expressed in another way.namely: if. at the time any oven is discharged, the age of the firstoven to the right is always the same and. likewise, if the age of thefirst. oven to the left is always the same. the pushing: (llt' i isuniform; and the ideal uniform series is one in which the age of hefirst right and [he first left oven to any given oven is exactly thesame. im-e it is iulprmjticable to have the ages of the first right andfirst left ovens exactly the same, the uniform series should be soselected that the first right and left ovens should be as nearly aspossible of equal a e; that is. as nearly as the best practice willpermit.

i In the accompanying drawings, I have illustrated by means of charts auniform pushing series and several of the pushing series used in thiscountry in such manner that the advantages or disadvantages flowing fromtheir use may be readily ascertained, and the general laws relating touniform series may be more easily deduced.

Figure 1 illustrating the -1l uniform pushing series shows also bycomparison, the relative ages ofall of the oveusin the series, as wellas the ages of the first adj acejnt ovens to any one being pushed, andalso the difference in the ages of any two ad'oining ovens. v

' lg. 2 "illustrates the 6-11 uniform pushing series, which, ashereafter described, is the complement of the 541 series, and in allreslapects its full equivalent.

igs. 3, 4, 5 and 6 illustrate respectively several of the irregular ornon-uniform pushin series, and are given for the purpose of showing at aglance the extreme irregularity of such series as compared with aregular uniform series such as shown in Figs. 1 and 2, and also toenable us to aualyze and make correct deductions of the effect of theuniform heating of the ovens.

In the following description, I shall first set forth the method. ofdeveloping the vari ous uniform pushing series, and then ascertain theresults and advantages to be derived from the use of several of the bestof these pushing series, and finally compare those results andadvantages with the results and disaovantages flowing from the use ofirregular or non-uniform series.

In order that a full umlerstanding of the process may readily follow, Ishall define some. of the terms used.

The conuuon practice at coke. plants is to discharge every 10th oven insuccession, and so the battery of ovens may he considered as containinga number of cycles" of ovens, each cycle having 10 ovens. Thus, abattery of 50 ovens should contain five of such cycles, the ovens in therespective cycles being numbered from 1 to 10, 1]. to 20, 21 to 30, etc.Ovens No. 1, 21, 31 and 41 are called No. 1 ovens of their respective cycles; likewise, ovens No. 4, 14. 24, etc, are the No. 1. ovens, etc. Thepushing series is then stated as the order or sequence of dischargingthe ovens of any cycle. The cycle may have any number of ovens, andalthough in general use, it will be shown that the Ill-cycle pushingseries are economically poor and inefficient as compared with certainother pushing series Where the. cycle is other than 10.

In order to greatly simplify the determination of the ages of adjacentovens in a battery, and to develop uniform pushin series, I have coinedthe term unit age", which may be defined as the coking tune divided bythe number of ovens in the cycle. Thus, when the coking time is 20hours, the unit age in a 10-cycle series is Qhours; likewise, the unitage in a -cycle series hecomes /15, or 1 hour and 20 minutes. The cokintime is, therefore, equal to the number of ovens in the cycle in unitages; thus, in the ltl cyclo, the coking time is 10 unit ages or 10units; in the 13-cyclc, the coking time is 13 units, etc,

In the development of the uniform pushing se ies, have used two methods,both of which reach the same results. I have called them respectivelythe interval method and the phase method,

The interval may be defined as the difference in the ages (in units) ofadjacent ovens. Thus, in the El-interval IO-cycle series, (called the3-10 series) each oven is 3 units older than the next oven to its right,and hence the relative ages of the ovens when ovcn No. 1 is pushed areshown by the following table Ovennumber 1 2 3 4 5 6 7 8 9 10 Rolativeage10 7 4 1 8 5 2 9 l1 3 Pushing order 1 4 7 10 3 6 9 2 5 8.

It will be observed that, although each oven is 3 units older than theone to its right, yet the coking time 10 must be added to ovens No. 4,7, and 10, for these ovens have ages 1, 2 and 3 respectively of thesucceeding charge of coal.

Since the coking time is 1.0 units, oven No. 1 is pushed first; afterone unit of time has elapsed, oven No. 8, which was 9 units old whenoven N 0. 1 was pushed, has arrived at the coking time, and is pushedsecond; two units after No. 1, oven No. 5 is pushed; and so on, in thesequence given in the pushing order numbers. Thus, the pushing order ororder in which all of the ovens of the cycle are pushed is determined.

From an examination of the table it will be observed that the sum of thepushing order and the relative age in units for any oven is always 11 inthe IO-cycle pushing series. Upon the production of other series, it canbe readily shown in general thatthe sum of the relative unit age and thenumber of the pushing order is alwaysonc greater than the number ofovens in the cycle. It may also be noted in any uniform pushing series,that the sum of the ages of the first ovens to the right and left of anyoven at the time such oven is pushed. is equal to the coking time inunits. .Thus, in the 3-10 series, when. any oven is pushed ac cording toregular schedule, the ageof the first oven to the right is 7 units, andthe age of the first oven to the left is 3 units. It may also benotedthat the pushingorder can be determined directly when the intervalis known, by merely adding the interval to the order number of theprevious oven, thus, in the 3-10+ series. 1

Ovennumbcr ..1 23 4 5 s 7 s 9 10 1 2 Pushingorder "14 710 3,6 9 2 5 8 14 Hence, if the interval is known, the pushmg order in any series may bereadily determined. For example, in the 5-11 series, the interval is 5and the number of ovens in the cycle is 11, and there also 11 units inthe coking time. Starting with oven No.1, its age when pushed is 11units; No. l oven is 5 units younger or its age is 6 units, and N0. 3oven is 1 unit old. The series fully developed is:

3 etc. 7 etc.

A-cycle. B-eycie.

OyenNo 1 2 3 4 5 6 7 8 9 1011 1 29m. Beluga ..11 6 1 7 2 8 3 9 4 10 5 11Gem. Push. order 1 6 1'1 5 104 9 3 8 2 7 1 Gate.

The above table is shown fully developed in Fig. 1 of the drawings, withthe ages of all of the ovens graphically illustrated. From a study ofthe figure or chart, it will be noted that when oven No. 1 is 11 unitsold and ready to be pushed, oven No. 2, or the first oven to the rightis 6 units old, and oven N o. 11 or the first oven to the left is 5units old. It will likewise be found that when each'oven has matured tothe coking;- age the first oven to the right will be 6 units old and thefirst oven to the left will he 5 units old. It will also be observedthat the sum of the first left and first right ovens equals 11 units, orthe coking time.

The other method of developing the pushing order I have called the phasemethod. In this method the pushing order in the various series is firstdetermined, and the relative ages of the ovens are then found from thepushing order. If, comm enciu g with oven No. 1, every nth oven of anycycle is pushed in rotation, 11 is called the phase. (Oven No. 1 followsthe last oven of any cycle, and hence in using the phase method, weshould consider the oven numbers in a cycle as lying 011 thecircumference of a circle). Thus, if every 3rd oven is pushed, 3 is thephase; likewise, in the lLcycle series, if every 9th oven is pushed, 9is the phase. In any %ivcn cycle, there is a fixed number of possi 1euniform pushing series, and all of them may be found by using; eitherthe phase or the interval method. he interval method has an advantageover the phase method, to be alluded to in the determination of the bestuniform series.

Since the interval method and the phase method of formulating pushingseries each give all the uniform series in any cycle, there is obviouslysome relation existing between the interval and the phase, or some wayof reducing the one to the other. This relation is given by thefollowing fOTlTllllfUI In the foregoing formuhc,

P is the phase number,

I is the interval number,

N is the number of ovens in the cycle, and

as is the smallest possible positive number that will make the value ofthe fraction an integer.

The following example will illustrate the relations on a 1.3-cycleseries Oven N0. l 2 3 4 5 6 7 8 9 10 11 12 13 A. push. OI 1 3 5 7 9 1113 2 4 6 8 10 12 B. push. Or 1 (i 11 3 8 13 5 l0 2 7 12 4 t] C. PUSI'LOT1 7 l3 6 1.2 5 ll 4 1O 3 9 2 S In A. 'iterval is 2, and phase is 7,since every 7th oven is pushed.

In B.'interval is 5, and every 8th oven is pushed.

In C. interval is 6, and phase is 11, since every 11th oven is pushed.

phase is 8, since In 'order to determine the phases by the use of theformula:

N is 13 and I is 6.

(In each case, a is given the smallest value that will make the fractionan integer.) In any iven cycle, the interval number and also the phasenumber must be prime to the. number of the cycle, that is, it cannot he:1 factor of, nor contain a factor that is common to, the cycle inunher.Thus, in the lO-cyelc series. the only possible interval or phase togive u uniform series is 8 and T. both of which are prime to 10. Theother numbers not being prime, any attempt to formulate L uniform serieswith then] as intervals or phases would be futile. Com ,iieiuentarvseries are found by merely reversing; the direction in both the intervaland phase method, and hence are fully equivalent in efficiency. In thelU-cycle series, the 3 intcrval is complementary to the 7-interval; alsothe 3-q hase is complementary to the 7-phase. ikewise in the ll-cycleseries, the 4 interval or phase is complementary to the 7 interval 01'phase; the 5 and 6 intervals are also complementary, us is raphicallyillustrated in Figs. 1 and 2, ant as previously stated, the 5-1] and the6-11 series are identical in form with the order of pushing reversed.Every uniform series, therefore, has its complcu'ieutury series; inother Words, uniform series occur in pairs, the interval or pl'iase ofany series being equal to the cycle number minus the interval or phaseof the comple iuentary series, The 11cycle series may have the followingintervals: 2, 3, 4t, 5, 6, 7 S and 9, since ul-lof these numbers areprime to 11; yet there are four distinct series only, since and 9, 3 and8, 4 and 7, 5 and 6 are respectively complementary intervals or phases.t

We are now able to develop all the regular pushing series, no matterWhat the cycle nray be; as above indicated, this may be dbne either bythe ii'rterval or by the phase method. In order, however, that therelative merits of the various pushing series should be made apparent,the following comparisons should be made:

1st. Whether or not the; pushing; series is uniform. 1

End. The difference in the adjoining ovens.

3rd. The sum and the difference of the ages Of any tlWQ ages of thefirst adjacent ovens on either side of any even when such oven ispushed. 1st. If the pushing series is uniform, all ovens should receivethe same heat treatment, and conversely if all the ovens receive thesame heat treatment, the pushing series must be uniform. It is perfectlyobvious that the pushing series should be uniform if a good. uniformseries could be selected and were practicable.

End. The difference of the ages of any two adjoining ovens should be asnearly as practicable equal to one half the coking time, in order, asalready stated, that the flue temperatures may be maintained more nearlyconstant. Therefore, a good uniform series is one in which the intervalis as nearly as possible one half of the coking time. It will therefore,be noted that an even number of ovens in a cycle is not as good or asefficient as; an odd number, because in an even numbered cycle. thenumber nearest to one half the cycle number is exactly one half thatnumber, and therefore not 'prime to it. This leads to the conclusionthat the best and most efficient cycle numbers must be odd. Furthermore,the best interval is determined by the formula Where n is the number ofovens in the cycle and odd.

. n tormmcd by the formula Where n is n the number of ovens and is even;or by the formula will a 2 when IS an odd numher.

It is thus apparentthat the best num ber of ovens in the cycle is an oddnumber; n 5

is even, and: the poorest when anodd the second best is an even nunbcrwhere number. Hence, a uniform series on the 104 cycle which is theone in common use is a very poor uniform series.

When the best interval in any 'oddn-umbored series is selected, thedifference in the ages of any two adjoining ovens is unit more or less.thanag the coking time, and consequently, sincelit is desired that thisdifi'erencehe as near as practicablcto Q; of the coking time, the unitof time Should be use 'iallus we can makeit; this-is, done by inciusing, the number of ovensin the cycle. 'lhere is, however, a practicallimit to the number of ovens in the cycle, for the reason thatcongestion of working about the oven'being charged and the oven being(lath charged is not desirable or economical; furthermore, a long travelof the pushin and leveling machines, door extractor and clay carriers isnot economical.

3rd. It was observed that in all uniform series, the sum of the a es ofthe first adjacent ovens to the rig t and left of any given oven whensaid oven is pushed, 1s equal to the coking time, and hence since theages of such right and left ovens should be as nearly equal as possible,they should each have an age as near to s the coking time as possible,or what amounts to the same thing, the difference in their-ages shouldbe as small as ossible. This method of consideration leads to exactlythe same results obtained in the next preceding paragraph.

In order that the advantages of my improved coking process may be mademore apparent, I have shown graphically in Figs. 3, 4, 5 and 6 severalof the pushing series now in use. Take for example the series shown in Fig. 3, which is as follows:

Oven number... 1 2 3 4 5 6 7 8 9 10 Pushingorder 1 5 9 7 2 4 10 6 8 3Relative age 10 6 2 4 9 7 1 5 3 8 Referring to the above table or toFig. 3, it will be noted that this is an irregular or non-uniformpushing series, and that the difference in the ages of adjoining ovensbeginningwith Nos. 1 and 2 are 4:, 4, 2, 5, 2, 4, l, 2, 5, 2 unitsrespectively. Two of the fines only are well heated, While in four ofthe lines the difference in the ages of adjoining ov'ens is only 2 unitsor 3% hours on 171} hour coke. The flue temperatures are, therefore,necessarily far from constant. Hence, the various ovens do not receivesimilar heat treatment. A similar examination of the pushing seriesillustrated in Figs. 4, 5 and 6 would show similar results as toheattreatment.

The unequal heating of the oven walls that results from the use of anirregular or non-uniform pushing, or the poor heating conditionsresulting fronia poor uniform series, gives risefto many of thedifiiculties in the operation of -by-product coking plants. Some ofthese may be enumerated as follows: In irregular pushing series, moreheat will enter through one of the oven Walls than through the other,and the central parting of the coke will not come in the center of thecharge, consequently resulting in a non-uniform coke. Again, in anirregular pushing series, the cokin time is neces sarily limited to thatof t a most slowly heated oven, and thus certain other ovens.

that are more favored by the pushin series will suffer by beingoverheated, whi e there will be a probable discharge at high perature ofthe volatile hydrocarbons which are cracked by these high temperatures,with a resulting decrease in the yield of the byproducts. The stickingof the coke charges in the ovens is traceable directly to unequal andirre ular heating. Since the determination of t e coking timeyas abovestated, is greatly controlled by the ovens found to he the mostdifiicult to heat, it follows that by the use of a good uniform pushingseries a reduction of the coking time must result, and the efiiciencyand capacity of the plant correspondingly increased.

These and other advantages flowing from the use of a good uniformpushing series as distinquished from an irregular or from a poor uniformseries may be thus sununuu ized:

A good uniform series will- 1st. Reduce the amount of gas burned in theoven fines, and consequently increase the amount of surplus gas.

2nd. Reduce the coking period or time to a minimum, because of lessdanger of irregu lar heatin and consequently iiurreusc the capacity orthe plant.

3rd. Improve the quality of the coke.

4th. Increase the yield of the by-products.

5th. Diminish the number of stickers, and consequently the number ofovens that are temporarily out of commission.

6th. Increase the life of the. plant.

7th. Diminish the operating expenses of the lant.

T 10 prevailin practice at the by-product coking plants where a pushingseries is used is to use some series on the 10-cycle It has thereforenot been necessary to difi'erentiate the various cycles in any way otherthan the direct method of consecutive numbers. However, when any cycleother than 10 is used, it becomes advisable if not absolutely necessaryto distinguish the cycles and the various ovens in the several cycles.This can be done in several Ways. If there are 9 ovens in the cycle, thenumbers 10, 20, 30, etc, may be omitted' If there are l}, ovens in thecycle, an extra number of a different notation may be inserted in each10, thus 1, 2, 358, 9, 10, X, 11, 12, 19, 20, 2X, 21, 22, etc. Wherethere are more than 10 ovens in a cycle, I prefer to give each cycle a,des-

ignating letter, as. A, B, C, D, etc., and then number the ovens of eachcycle consecutively. Thus 4A is the 4th oven of the first cycle; 7l3 isthe 7th oven of the 2nd cycle, etc. By thus distinguishing the ovens inthis or any similar way, there is. far less confustion with regard topushing the proper ovens; for example: al of the ,1s are pusl d in allof the cycles, and then, say, all of the 3s,,etc. VYhen it is consideredthat the workmen who are actually engaged in operating the plant are notally of a high order of mentality, the importance of a simple method ofdesignating the ovens and cycles cannot be overestimated, particulerl"where there is a change from existing con itions.

From the foregoing, it will be seen that l have added in]importantimprovement to existing coking processes, and 1 thereforedesire to claim the some broadly.

1. A coking process consisting of arranging a battery of coking ovens init series of cycles, each cycle containing a number of ovens, andthereafter charging and dischnrging said ovens in such regular orderthat the difference in the ages of every two udjoiningovens shall beconstant.

2. A coking process consisting of arranging u battery of coking ovens inu serie.-; of cycles, cu-ch (:J'lli containing N ovens, and thereaftercharging and discharging .-,u'nl ovens in such order that the differencein the nges oi r m two adjoining evens shall he i1 units of time when Nis an odd. num- N -2 her: that said diiim'cnre shell hr- 7 units of timewhen N/L) is an even number; and

that said difference shall be units of time when N/Q is an odd number.

3. A coking process consisting of arming ing a battery of coking ovensin :1 series oi cycles, each cycle containing the same munher of ovensand thereafter charging and discharging said ovens in such order thatthe difference in the ages of every two mljoining ovens shall beconstant.

4. A coking procees consisting of arranging a battery of coking ovens ina series of cycles each containing an odd number oi ovens. andthereafter charging and di charging the ovens in any cycle in a regularorder such that every nth oven of each cycle shall be discharged inturn, Where it is :1 number prime to the number of ovens in each cycle.

5. A coking process consisting of arrangingabatteryof coking ovens in aseries of cycles,ea-c cgcle containing a, number of ovens,. and tereafter charging, and dis charging'saicl ovens inje regular order suchthat every nth oven of each cycle shall be discharged in turn, Where nis a number prime tothe number of ovens each cycle.

6. A coking froce ss consisting of arming ing a, battery 0 coking ovensin series of cycles, each cycle containing anocld number of ovens, andthereafter charging and discherging said-evens in such order that thediil'et'ence ingthe ages ofthe ovens immediiitely adjacent tothe'riglit' and left of any giverhoven shall be constnnt in the severalcycles;

7. A coking process consisting of arranging a battery of coking ovens ine series of cycles, each containing an odd number of ovens, andthereafter chin-gin and dis charging said oveiis in such or er that thed'ifi'eii'ence in the a es of the ovens immediutely adjacent to t eright and left of any given oven bein' discharged shall be the cokingtime divi ed by the number of ovens in the cycle.

8,' A coking process consisting of among ing a' battery of coking ovensin :i series of cycles, each c (the containing an odd number of'ovens,rind thereafter charging and discher'g ng said ovens in such regularorder that the sum of the ages of the ovens imincdietely adjacent to theright and left of the oven being discharged shall be equal in thecokii'ig time.

' A coking prom; fiUllulbilllg oi urrungmg a battery of coking ovens inn cries or cycles, each cycle containing n11 odd number of ovens andthereafter charging and ill. harging suid eve in ::ii"l1 regular orderthat the age of every men hllilll he l::-- than the age of the oven nextadjacent thereto by :1 number of unit ages that is prime to the numberof ovens in the cycle.

10. A coking process consisting of arranging a battery of coking ovensin a, series oi cycles Wit-h. the some number of ovens in enchcyele, andthereafter charging and dis charging said ovens in such reguhir orderthat the difi'ercnce in the ages of the ovens immediately adjacent tothe oven bring di charged shall be uniform.

1 11. A coking process consisting of arranging 11 battery of cokingovens in e series of cycles, each containing vthe some odd nuinber ofowns, and thereafter charging and discharging said ovens in such regularorder that the res ective ovens as thei are dis charged shal haveattained the cdking time, and the two oyens immediately adjoining theone being discharged shell here attained ages who'se sum shall equal theraking time. 12, A coking process substantially as set forth i lugl aim1, in which the Qffillfis 0-15 each cycle ere eensecuti gely numbered,and the several cycles are designated a, distinctive ymbo i I3. cokingrecess substentielly as set forth in cleinr in which eechcyeleisdesignated hy a, distinctive lettereas A, B, C

etc encl the ovens of each cycle are consecutively num cred i 14'; A 00mg process snbstantially as set f r h; claim 4,111, whi heach cycle sdesig noted, y d istinctivesyinbohand, the ovens ofj gee c cie zireeonsec'utively numbered, whereby to; eel tate then-regular end uniformoperation.

w, B. MARQUARD.

